On Wed 23-01-13 07:22:49, Carlos Maiolino wrote: > On Wed, Jan 23, 2013 at 11:39:17AM +0100, Jan Kara wrote: > > On Tue 22-01-13 11:07:58, Carlos Maiolino wrote: > > > This checks for incompatible mounting options when using ext4 module to mount > > > ext3 or ext2 filesystems. > > > > > > Sets two new flags to group ext4 mount options that are incompatible with ext2 > > > and ext3, and then add two functions -- check_ext2/3_incompat_mount() -- to > > > check and warn/fail mount, if any of these options are being used. > > > > > > I believe, some options like those expecting an argument needs to be checked > > > during parsing time. > > > > > > barrier mount, although it has a flag, when mounting an ext2fs, where > > > barriers are not supported (afaik), should also be checked during parse > > > time, otherwise the BARRIER mount flag will be set. > > > > > > I didn't add all mount options I believe to need to raise a warning, just > > > those with a flag set on superblock, another flags should be added after a > > > discussion to reach a concensus of all ext2/3 options that should be rejected by > > > ext4 mount. > > Thinking about it a bit more I'm not sure if restricting mount options is > > the right thing to start with. IMHO what we should restrict is mounting > > filesystem with certain *features* as ext3/ext2. So e.g. filesystem with > > EXT4_FEATURE_INCOMPAT_EXTENTS cannot be mounted as ext2 or ext3. Similarly > > as currently we forbid mounting ext3 filesystem with > > EXT3_FEATURE_INCOMPAT_RECOVER as ext2... This should avoid the confusion > > which could arise when someone reports problems with "ext3" filesystem but > > actually has some of the ext4 features enabled. > > > This is interesting, but I wonder if not restricting mount options, but > features, would open a 'window' to let users change their filesystem on-disk > format without know what they are doing, but I might be wrong. If there are mount options that enable features, then these should be disallowed for ext2/ext3 mounts. But I think we already got rid of these traps on users... Honza -- Jan Kara <jack@xxxxxxx> SUSE Labs, CR -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
